The four principles of natural selection are variation (organisms within a population have their own individual differences in their appearance, such as, markings and color), inheritance (traits passed down to the offspring), high rate of population growth (which leads to their local resources to be more of a challenge to find), and differential survival/ reproduction (organisms in the population with stronger traits are more likely to survive and reproduce, aka survival of the fittest). These four principles work together to respond to chance in the environment by making sure the strongest survive and over time that species will adapt to their environment because the organisms with the better suited traits will pass their traits to its offspring.
When the two different population species interact in such a manner that it is beneficial to each other, then this form of interaction is called mutualism.
